1. Field
One or more embodiments of the present invention relate to rendering, and more particularly, to a 3D graphics accelerator supporting a pipeline structure which is not programmable, that is, a fixed function pipeline structure.
2. Description of the Related Art
A conventional rendering apparatus supporting a fixed function pipeline structure performs a number of fixed graphics operations on each of a plurality of fragments generated for every plane formed of a plurality of vertices in order to perform rendering (that is, visualization) on a model constructed with the plurality of vertices. In this case, the graphics operation may be an operation of displaying fragments as pixels such as when texture mapping, or an operation of testing whether the fragments can be displayed as pixels such as when performing a depth test. Here, texture mapping denotes mapping information on quality and texture of a 2D image to a fragment, and performing a depth test denotes testing whether a fragment to be displayed can be displayed as a pixel by comparing a depth value of the fragment and a depth value matched to a displayable position of the fragment.
The conventional rendering apparatus, and more particularly, a rendering apparatus supporting a fixed function pipeline structure according to an open graphics library (OpenGL) proposed by the OpenGL architecture review board performs graphics operations of testing whether fragments can be displayed as pixels, after performing one or more graphics operations of displaying fragments as pixels. Accordingly, the conventional rendering apparatus performs unnecessary graphics operations of displaying fragments to be tested as pixels, that ultimately cannot be displayed as pixels. This creates a problem in that efficient power consumption and rapid completion of rendering are difficult to achieve. The problem can increase when the conventional rendering apparatus performs a graphics operation, such as texture mapping, that has a large operation capacity to display fragments as pixels.